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Lehigh Tunnels

NATM design, instrumentation and construction supervision services; waterproofing system design and rehabilitation support services.
Estimated cost: Commencement:
March 25, 1987
Completion date:
December 25, 1991
Route 283, Eisenhower Blvd
Allentown, PA 17034
United States
Technical data:

New highway tunnel, two lanes, 28 ft (8.5 m) x 40 ft (12.1 m) x 4,265 ft (1300 m). Constructed using NATM with drill and blast excavation measures. Installation of PVC membrane and thermal insulation in air duct of the 50 year old, two lane road tunnel during rehabilitation. Tunnel lenght: 4,138 ft (1260 m); waterproofed area: 117,000 sqft (10870 m²).

Geology description:

Sandstone, shale, siltstone.

Geology types:
Bid cost: Final cost:
$25 million USD
Service areas:

The Lehigh Tunnel No.2, part of a 4-lane motorway running East-West through Pennsylvania, was one of the first tunnels in the US built using NATM. Capacity problems of Lehigh Tunnel No.1 caused delays during peak times. The new tunnel was excavated using top heading, bench and invert excavation with shotcrete support. To achieve a completely dry tunnel a PVC membrane was installed between primary shotcrete lining and the final cast-in-place lining. Tunnel rehabilitation including the installation of a PVC membrane and thermal insulation in the air duct was performed to the original tunnel.

Ventilation duct with ice build-up
Installation of waterproofing system
Typical Cross Section
View of exisiting Tunnel Portal
Preparing Tunnel Portal to start Excavation
Tunnel Face with Shot Holes ready to blast
Formwork for Cast-in-Place Final Lining
Final Lining and Invert Drain Trench
Lehigh Tunnel No. 2 - Completed Southbound Portal
Lehigh Tunnel No. 1 - before Rehabilitation
Frozen Water Leakage in Upper Air Duct
Lehigh Portals Tunnel No. 1 (left) and the new Tunnel No. 2
Spiles and anchor
Spiles and anchors
seeping water
Profile check
Essembling the formwork
Incident doing form essembling
Glossy tunnel walls
Glossy tunneling
Finished tunnel
Reinforcement of roadway
Lehigh Tunnel #1 & #2 South Portal